Advancing Mooring Technology for Long-Term Ocean Observation

Advances in oceanographic mooring technology are critical to sustaining long-term, high-quality observations in some of the planet’s harshest environments. Moorings must now operate reliably over extended deployments, support increasingly sophisticated instrumentation, and withstand the growing impacts of extreme weather. To better understand recent progress and ongoing challenges in this field, we spoke with Alex Franks, Research Engineer at Woods Hole Oceanographic Institution (WHOI) and a key contributor to the Ocean Observatories Initiative (OOI).

Over the past three years, Franks and his team have introduced significant upgrades to OOI infrastructure – most notably enhancements in satellite telemetry, power generation and management systems, and the structural resilience of both surface and subsurface moorings. These improvements aim not only to extend deployment lifetimes and reduce maintenance needs but also to expand the scientific capabilities of moorings by accommodating higher-bandwidth data streams and more energy-intensive instruments.

This Q&A offers a detailed look at the evolving strategies behind mooring system engineering and the practical steps being taken to meet both scientific demands and environmental challenges.

1. In the last 3 years, what have been the most notable improvements in remotely diagnosing and fixing mooring issues?

The biggest upgrade we’ve implemented recently is a new satellite telemetry module called the “Stream +” (Stream Plus). This allows us to communicate with the buoys in a faster and more streamlined manner. I would compare the upgrade being the difference between dialup and high-speed internet. This unit was originally tested on the Irminger Sea Surface Mooring deployed in 2024 and has now been deployed at the Pioneer Array on the Central Surface Mooring and one of the Profiler Moorings. With this increased ability to troubleshoot and interact, we are able to support high bandwidth instrumentation like the Mclane IFCB (Imaging Flow Cytobot) which takes pictures of phytoplankton in real time. We are able to download a subset of the images and adjust camera focus remotely now. OOI can now also accommodate proposals for more high bandwidth instrumentation on the buoy systems.

2. What new features are you currently developing to further improve mooring system reliability?

The OOI Electrical Engineering group is currently focusing on reducing power consumption and increasing reliability of power generation systems on the Surface Moorings. Several systems are being optimized including individual instrument power supplies and Surface Mooring seabed-located multifunction node (MFN) power transmission. We are also upgrading the solar panels to harvest even more energy from the sun during long deployments. Lastly, the wind turbines on the Surface Moorings have been further ruggedized to help withstand the 20-meter waves and hurricane force winds that we observe at our global sites. A test of that redesign is underway at the Pioneer Array. All of these optimizations and upgrades will result in a mooring that can accommodate new power-hungry instrumentation, exceed our current sampling scheme, and withstand doldrums or high latitude winter with little to no solar generation.

At OOI we are also starting to think about more onboard computing power, more data storage, and more expandability in terms of available ports for new instrumentation. We always have our eye on streamlining our current electronics.

3. Looking ahead, what do you see as the next major breakthrough in mooring technology?

I’m looking forward to testing solid state batteries as they are developed for use on mooring systems. The benefits of lithium with less safety concerns are very interesting to me. Losing battery weight and gaining more usable energy storage is a very attractive prospect.

4. Are there any upcoming field tests or deployments that you’re particularly excited about?

OOI is partnering with Sandia Labs and the Department of Energy to develop and deploy a prototype of a wave energy converter on the Central Surface Mooring in fall of 2025. This device will be situated inside the buoy and convert wave motion into mooring power as proof of concept. This project has been going on for a few years now and it’s very rewarding to see it coming to fruition.

Advancements in mooring technology are directly improving data quality, reliability, and access for long-term ocean observations.

To explore available datasets and learn more about current system capabilities, visit oceanobservatories.org.

Compass characterization procedure at the LOSOS building. Pictured: Alex Franks, WHOI